Your confusion is driven by two diametrically opposed principles of learning the arts. The first is the modern eclectic perspective of kenpo created by Ed Parker Sr. (or perhaps other arts driven by Bruce Lee), which requires degrees of tailoring to be commercially successful. This interpretation has little or no defined physical basics, and is a conceptually driven vehicle. It promotes the ideas that you articulated.
The second is the reality seen in the traditional arts that says you must learn proper physical basics and be taught by a highly skilled and knowledgeable teacher. This requires consistent, corrected, and focused learning not generally available in the motion based vehicle. It does not allow variations based on personal preferences until such time you have mastered basic skills, and core principles of execution. Therefore, it is not generally suitable for a commercial business, but in fact does contain the information needed to make the intelligent decisions to begin the true tailoring process promoted in the first.
These are obviously major contradictions. One designed for commercial success, and supply a reasonable level of martial skills but only commensurate with the knowledge, skill, and commitment level of the teacher. The other is designed to take you to higher levels of skill and knowledge, but is initially restrictive in the learning process. The average person does not have the commitment for the second, nor is it especially suitable intellectually for the children that drive the commercial market.
Thus, you like many others are caught in a dichotomy of philosophies. Those reared in the commercial market of the arts are often led to believe the commercial philosophy is the prevailing and best methodology, and in fact commercially, it is and its popularity confirms that.
Nevertheless, the personal preferences of tailoring lead to a functional ceiling of skill and knowledge that is born and bred into its teachers. We all laugh at the old Chinese movies where the teacher corrects the smallest of details over, and over again. However this is actually how you must be taught if you wish to have the foundation that will allow you one day to make those tailoring decisions from a perspective of real knowledge and not concepts.
So tailoring is good and in abundance in the traditional Chinese Arts, and that is where all the different family styles come from. However tailoring is an old concept better left to those who know what they are doing after years of proper training under a keen knowledgeable teacher. Parker simply allowed everyone in his commercial arts to do whatever they wanted, as long as they were satisfied with the results. This is pure genius. If you didnt like the results, you can only blame yourself. He only gave you guidelines.
Bottom line, you cant have it both ways. The commercial arts, (especially kenpo), is full of martial scholars who dont have the knowledge or the skill to back up or even understand what they do yet. However, because of the lack of truly qualified teachers, most have no choice. It is essential under these circumstances to lower expectations of what the vehicle you have chosen is capable of delivering, and ignore the criticism of all but the most qualified of teachers. Even then, ask for physical verification of any idea or concepts.
Most will more likely look to other more traditional arts to fill in the holes, however this method too is flawed. Grafting various arts brings its positives and negatives. Unfortunately, it takes a knowledgeable teacher again to know the difference.